Photographic processing apparatus



Feb. 17, 1970 E. E. SCHUMACHER PHQTOGRAPHIC PROCESSING APPARATUS FiledSept. 27, 1957 R m M w E T SC HUMACHER United States Patent O 3,495,520PHOTOGRAPHIC PROCESSING APPARATUS Ernst Eugen Schumacher, 3113 Postfach,6 Frankfurt am Main 1, Germany Filed Sept. 27, 1967, Ser. No. 671,083Int. Cl. G03d 3/12 U.S.-Cl. 95-94 7 Claims ABSTRACT OF THE DISCLOSURE Acontinuous photographic film processing apparatus having at least threetanks arranged side-by-side and each containing a processing fluid. Themiddle one of the tanks has a gas-tight cover extending over theadjacent end of each of the other tanks and also has end walls extendingbelow the surface of the fluid in the other tanks. When film istransported serially through the tanks it must pass under the respectivecover and end walls to enter and leave the middle tank. The cover andend walls provide a seal which prevents air from the outside frompenetrating into the gas-tight closed space.

BACKGROUND OF THE INVENTION Photographic processors are designed totreat an exposed photographic film in different baths according to apre-set program. Generally the successive baths are:

(1) A developer-solution to reduce the halogenous silver in thephotographic emulsion, where a latent image was produced during theexposure; the developer-solution usually contains reducing agents incombination with stabilizers, an alkali and a moderator;

(2) A fixing bath, dissolving halogenous silver, forming with same awater soluble complex compound;

(3) A water bath for rinsing.

In case of special photographic processes, further baths may berequired. Processors are provided with transport or conveyor systems,shifting or carrying the film through the bath tanks and from one to thenext in the predetermined sequence.

It is well-known that developer solutions are liable to be deterioratedby oxydation of the reducing agents therein, effected by the oxygen ofthe air being in contact with the surface of the bath. In case ofdevelopers for continuous-tone films, it is, however, possible tocounteract oxydation by adding stabilizers to the solution. On the otherhand, there are special developers, oxydation of which is nearlyimpossible to prevent, whenever they come in contact with the air; thisis true particularly for socalled lith-type developers, which areindispensable in the technique of process reproduction. The highsensitivity of such lith-type developers to the oxygen of the air ismainly due to their contents of paraformaldehyde or similar products.

SUMMARY OF THE INVENTION The aim of the present innovation is aphotographic processor wherein the space above those bath tankscontaining oxygen sensitive solution is closed off completely gas-tightfrom ambient atmosphere, and having means of transport to introduce thefilms in said baths and to remove them upon completion of the treatmentthrough fluid seal means which prevent air from the outside to penetrateinto the gas-tight closed space.

This aim is materialized according to the present invention by aphotographic processor, having a roller or belt film-conveyor system,characterized by a construction wherein before and after the tankcontaining an oxygen sensitive solution, or a multiple of such tanks,there is provided a seal tank containing a solution which is not oxygensensitive; and wherein at least two gas-tight fences dip into theliquids contained in each one of said seal tanks, the conveyor systemleads the film in such a way that it passes underneath said fencesdipped into the liquids in the seal tanks, and the fences are fixed to acover or hood hermetically closing the space not only above the tank ortanks, containing the oxygen sensitive solutions, but also parts of bothof the adjacent tanks inside of the said fences.

Preferably the lower edges of said fences will dip at least 10 mm. underbath level of the two fluid-seal tanks, containing the solutions whichare not oxygen sensitive.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic side elevationalview showing the center part of a photographic film processing apparatusaccording to the invention, and having three (3) tanks and a rollerconveyor system for film transport from tank to tank, and

FIG. 2 is a fragmentary prospective view, with parts broken away,showing details of the gas-tight connection between the sealing endwalls of the cover means and the side walls of the sealing tank.

DESCRIPTION OF THE PREFERRED EMBODIMENT The function of the processorembodying this invention may be described, for instance, as follows:

The exposed film is placed on a feeding table of the processor andtransferred by the conveyor belt or the conveyor rollers into a firstbath, which is not as usual the developer bath, but a mere preliminaryor wetting bath, containing a liquid, not sensitive to the oxygen of theair. The film is forced by the conveyor system to pass downwardsunderneath the first fence, dipped from above into said bath. Havingunderpassed the fence, the film is lead upwards so as to come out of thefirst bath and to enter the hermetically closed space, from which itwill be introduced in the oxygen sensitive bath, e.g., the developerbath. After passing through the oxygen sensitive bath, the film entersagain the hermetically closed space above the oxygen sensitive bath fromwhich it is introduced in the subsequent bath which is not airsensitive, e.g., the stop bath or fixer bath. Here the film is againforced to underpass the fence, dipped therein, so as to come out of thebath in the ambient atmosphere beyond the fence. The further way of thefilm in the processor is not part of the invention.

As to the composition of the two baths, adjacent to the oxygen sensitivebath or baths, the only condition is that they ought not be airsensitive. In case of the described lith-film development thepreliminary 'bath can be functional, but must not be functional in thesense of the developing process. It may be a pure water bath, orcontaining, in addition, wetting agents or weak alkali, desensitizers oraccelerators or even parts of the developer or regenerator, in as far asthey are not oxygen sensitive or at least not noticeably sensitive inthe dilution or pH range prevailing in the preliminary bath. Also it ispossible to use organic liquids, provoking no or only limited swellingeffect on the photographic emulsion.

In any photographic development process one or more baths subsequent tothe developer bath will be necessary, one of which will not, in anycase, be air sensitive. Therefore, no additional tanks or prolongationof the conveyor system is necessary to equip the processor with thehermetically closed space as per the invention. In such cases, the twofences may form part of the cover or hood on top of the tank containingthe oxygen sensitive bath.

It is clear, that the hood must be removed in case of cleaning orrefilling the machine. Accordingly, in this event, there is atmosphericair in contact with the developer. This will normally be negligible,since it represents only a small quantity of oxygen, which is notrenewed in the course of use of the machine, however, the protection ofthe developer against oxydation can be improved by replacing theresidual air in the closed space by an inert gas, such as nitrogen.

The top of the closed space may be dome-shaped or plane, resting on theside walls of the tanks to be covered. Tightening may be obtained byelastic stripes or any other suitable means. Also, the fences must beremovably fixed gas-tight to the sidewalls of the tanks and to the top.

In FIG. 1 there is shown the first or preliminary tank 1, the tank 2containing the oxygen sensitive bath and the tank 3 holding a fixingbath. The film will be transferred along the arrow-marked line by amultitude of rollers or pairs of rollers. The first fence 4 is dippedfrom above into the tank 1, the lower edge of the fence being at least10 mm. or more underneath bath level 7. The second fence 5 is dippedinto the tank 3. The coverplate 6, in combination with the upper edgesof the fences 4 and 5 and the side walls of the tank assembly, forms theclosed space into which the film can enter and out of which it can beremoved without air penetrating from outside.

FIGURE 2 shows in detail how a gas-tight connection can be obtainedbetween a removable coverplate 6, to which a fence 5 is fixed, and asidewall 8 of a tank 3. The conveyor rollers are not shown. The coverplate is partly broken away to show details inside the assembly. Anglebars or lugs 9 and 10 are fixed to the side wall 8 in back to backrelation to form a channel into which the fence is inserted, and thischannel is lined throughout with an elastic or plastic coating material12 to provide an air-tight seal. The top of side wall 8 is also fittedwith a sealing strip, as at 11, on which the cover plate rests bygravity. The nozzles 13 and 13', with suitable valves not shown, permitreplacement of the residual air by an inert gas, i.e., by means of ahose from a nitrogen supply connected to one of them. With both valvesopen, the nitrogen let in one valve will push the air out through theother valve following which both valves will be closed.

I claim:

1. A film processing apparatus comprising at least onebath chamber forcontaining an oxygen sensitive process ing fluid, means for conveyingfilm into and out of said one bath chamber, first and second sealingchambers respectively disposed ahead and behind said one bath chamberfor containing fluid not oxygen sensitive, and a gas-tight closure meansfor said one bath chamber extending over and enclosing at least theportions of said sealing chambers adjacent said one bath chamber, saidclosure means having end walls extending into respective ones of saidsealing chambers to a point below the normal fluid level therein, andsaid conveying means extending into and out of each sealing chamber andbeneath the respective closure means end wall therein.

2. A film processing apparatus according to claim 1 wherein the" saidone bath chamber holds a fluid containing heavy gas.

3. A film processing apparatus according to claim 1 wherein the said onechamber and the sealing chambers are disposed side-by-side within acommon housing.

4. A film processing apparatus according to claim 1 wherein the closuremeans is removable for access to the interior of the apparatus.

5. A film processing apparatus according to claim 4 wherein the closuremeans end walls have a sliding gastight connection with the side wallsof the respective sealing chambers.

6. An apparatus according to claim 1 .wherein the said closure means isprovided with a valved gas inlet and a valved gas vent.

7. A continuous film processing apparatus comprising at least oneintermediate bath chamber (2) disposed between a pair of end bathchambers (1, 3) all said chambers being disposed side-by-side in alineal series, and each of said chambers being in the form of anopen-top tank adapted to contain fluid to a predetermined level, theedges of the top openings of said chambers being in a common plane. Agas-tight closure means (6) extending from one end chamber to the otherin a gas sealing relation with the top edges of all said chambers, saidclosure means extending over the inner portions only of the end bathchambers and having end walls (4,.5) extending downwardly into therespective end chamber to a point below the normal fluid level (7)therein, and a References Cited UNITED STATES PATENTS 2,389,378 11/ 1945Marisic.

2,458,394 1/1949 Luboshez -94 XR 3,023,686 3/1962 Meyer 95--94 3,375,5934/1968 Fleisher et a1. 95-89 XR JOHN M. HORAN, Primary Examiner ROBERTP. GREINER, Assistant Examiner Us. (:1. X.R. 9589

